Document Type : Research Article
Authors
1
Associate Professor, Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
2
Ph.D.in Geomorphology, Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
3
MSc. Student, Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
Abstract
Floods are the most common natural hazard in the world, destroying human lives and property. The impact of floods is a function of several criteria: flood strength and magnitude, repetition and duration of flood and geometry of river crossings. Evaluation of flood-prone areas on a regional scale to manage the catchment area and reduce potential casualties is of great importance. The aim of this study is to prepare a flood susceptibility map using a combined analysis of hydro geomorphic criteria and a hierarchical analysis process (AHP) to achieve this goal 12 criteria such as: elevation factor, slope, Distance from river, Geomorphology, Drainage density, Flow accumulation, precipitation, land use, geology, SPI, TWI, curvature. SPI, TWI, curvature layers in SAGA GIS environment have been prepared and the other layers have been prepared in GIS environment. After preparing the criteria, the pairwise comparison matrix is prepared and then the value of the final coefficient of the layers is prepared with the help of Expert Choice software. Then all the factors are classified and fuzzy normalization is applied to them using fuzzy functions. Finally, all layers are merged using the WLC method and the final map is prepared. To determine the degree of correlation of layers using random points, the correlation coefficient of factors has been calculated. The results of this study show that in the Sanghar catchment area, about 26% of the area is exposed to high and very high flood sensitivity and 59% have low and very low flood sensitivity. Among the geomorphic factors affecting the flood, three factors: elevation, slope, and drainage network density have a major impact on the flood sensitivity of the Sanghar catchment; In contrast, the four factors of Distance from river, SPI, Flow accumulation and curvature played a smaller role in the flood susceptibility map of the Sanghar catchment.
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